Impact indicators are too old or too young to be remnants of an ancient comet that sparked climate change at the end of the Ice Age, killed America’s earliest people and caused a mass animal extinction, study says.

New findings may settle a decades-long debate over how nitrogen is removed from the ocean. Understanding nitrogen cycling is crucial to understanding the productivity of the oceans as well as the global climate.

New scientific studies at the La Brea Tar Pits are probing the link between climate warming and the evolution of Ice Age predators, attempting to predict how animals will respond to climate change today.